Semiconductor device fabrication processes in advanced technology nodes generally require state of the art deposition methods for forming transition metal containing films, such as, for example, elemental transition metals, transition metal oxides, transition metal nitrides, transition metal silicides, transition metal phosphides, transition metal selenides, or transition metal borides.
A common requisite for the deposition of transition metal containing films is that the deposition process is extremely conformal. For example, conformal deposition is often required in order to uniformly deposit a transition metal containing film over three-dimensional structures including high aspect ratio features. Another common requirement for the deposition of transition metal containing films is that the deposition process is capable of depositing ultra-thin films which are continuous over a large substrate area. In the particular case wherein the transition metal containing film is electrically conductive, the deposition process may need to be optimized to produce low electrical resistance films.
Cyclical deposition processes, such as, for example, atomic layer deposition (ALD) and cyclical chemical vapor deposition (CCVD), sequential introduce one or more precursors (reactants) into a reaction chamber wherein the precursors react on the surface of the substrate one at a time in a sequential, self-limiting, manner. Cyclical deposition processes have been demonstrated which produce metal containing films with excellent conformality with atomic level thickness control.
Cyclical deposition processes may be utilized for the deposition of transition metal containing films, such as, for example, copper containing films, nickel containing films, and particularly cobalt containing films. However, chemical precursors suitable for the cyclical deposition of transition metal containing films, and particularly cobalt containing films are uncommon and cost prohibitive. For example, existing chemical precursors utilized for the cyclical deposition of cobalt containing films may require undesirable high temperature deposition processes and/or the use of plasma enhanced deposition processes. In addition, cyclical deposition processes utilizing existing cobalt chemical precursors may be undesirable due to the sensitivity of the deposition process to the material of the underlying substrate. Accordingly cyclical deposition methods, chemical precursors suitable for use in cyclical deposition processes and related vapor deposition apparatus are desirable for the formation of transition metal containing films, and particularly cobalt, copper, and nickel containing films.